Very important part of the language learning process is vocabulary and especially when you are learning more than one language.
Learning words by making sentences is the most preferable method I have adopted. Pick up any damn word and make a sentence. It is very effective. It is your brain that needs training when it comes to learning words. Involuntarily when words come to your mouth and when they are right you can reassure yourself thar you are on the right track. But it is not all. It is a long process. I don't discourage but try to inspire.
Words and play with words through repetition and interesting excercises is one of the keys to language learning. Passion and tremendous will will ease your journey to being a language expert.
"Wortschatz" in German and словарь in Russian is vocabulary what we call inE Learning new words out of curiosity can also be a good habit. Pick up a word in English , refer a dictionary and add a word in your collections. It is a big ocean of words waiting for you. You love them they come to you.